sscanf

(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)

sscanf — Analyse une chaîne à l'aide d'un format

Description

sscanf(string $string, string $format, mixed &...$vars): array|int|null

sscanf() est l'inverse de la fonction printf(). sscanf() lit des données dans la chaîne string, et l'interprète en fonction du format format.

Tous les caractères blancs dans la chaîne format correspondent à un caractère blanc dans la chaîne string. Cela signifie que même une tabulation (\t) dans la chaîne de format peut correspondre à un simple espace dans la chaîne str.

Liste de paramètres

string

La chaîne à analyser.

format

Le format interprété pour string décrit dans la documentation de la sprintf() avec les différences suivantes :

La fonction ne tient pas compte du contexte local.
F, g, G et b ne sont pas supportés.
D représente un nombre décimal.
i représente un nombre entier avec détection de base.
n représente le nombre de caractères traités à ce stade.
s arrête la lecture à chaque caractère d'espacement.
* au lieu de argnum$ supprime l'affectation de cette spécification de conversion.

vars

Optionnellement, vous pouvez passer des variables dans ce paramètre, par référence qui contiendront les valeurs de l'analyse.

Valeurs de retour

Si seulement deux paramètres sont fournis, les valeurs trouvées seront retournées sous forme de tableau. Sinon, si le paramètre optionnel sont fourni, la fonction retournera le nombre de valeurs assignées. Le paramètre optionnel doit être passé par référence.

S'il y a plus de sous-chaînes attendus dans le paramètre format, qu'il y a de disponibles dans string, alors null sera retourné.

Exemples

Exemple #1 Exemple avec sscanf()

<?php
// Lecture d'un numéro de série
list($serial) = sscanf("SN/2350001", "SN/%d");
// et la date de fabrication
$mandate = "January 01 2000";
list($month, $day, $year) = sscanf($mandate, "%s %d %d");
echo "Le produit $serial a été fabriqué le : $year-" . substr($month, 0, 3) . "-$day\n";
?>

Si des paramètres optionnels sont passés, sscanf() retournera le nombre de valeurs assignées.

Exemple #2 sscanf() - utilisation des paramètres optionnels

<?php
// lit les informations d'auteur, et génère une entrée DocBook
$auth = "24\tLewis Carroll";
$n = sscanf($auth, "%d\t%s %s", $id, $first, $last);
echo "<author id='$id'>
    <firstname>$first</firstname>
    <surname>$last</surname>
</author>\n";
?>

Voir aussi

printf() - Affiche une chaîne de caractères formatée
sprintf() - Retourne une chaîne formatée
fprintf() - Écrit une chaîne formatée dans un flux
vprintf() - Affiche une chaîne formatée
vsprintf() - Retourne une chaîne formatée
vfprintf() - Écrit une chaîne formatée dans un flux
fscanf() - Analyse un fichier en fonction d'un format
number_format() - Formate un nombre pour l'affichage
date() - Formate un horodatage Unix

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User Contributed Notes 18 notes

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jon at fuck dot org ¶

22 years ago


this function is a great way to get integer rgb values from the html equivalent hex.

list($r, $g, $b) = sscanf('00ccff', '%2x%2x%2x');

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elgabos at umail dot ucsb dot edu ¶

22 years ago


After playing around with this for a while, I found that if you use %[^[]] instead of %s (since php has problems with spaces when using %s) it works nicely. 

For those that aren't familiar with regular expressions, %[^[]] basically matches anything that isn't nothing.

Hope this helps. - Gabe

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mikewillitsgmail.com ¶

16 years ago


FYI - if you are trying to scan from a string which contains a filename with extension. For instance:

<?php

$out = sscanf('file_name.gif', 'file_%s.%s', $fpart1, $fpart2);

?>

The scanned string in the $fpart1 parameter turns out to be 'name.gif' and $fpart2 will be NULL.

To get around this you can simply replace the "." with a space or another "white-space like" string sequence.

I didn't see any other comments on regarding string literals which contain a '.' so I thought I'd mention it. The subtle characteristics of having "white-space delimited" content I think can be a source of usage contention. Obviously, another way to go is regular expressions in this instance, but for newer users this may be helpful.

Just in case someone else spent 10 minutes of frustration like I did. This was seen on PHP Version 5.2.3-1ubuntu6.3.

Searching the bug reports shows another users misunderstanding: http://bugs.php.net/bug.php?id=7793

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Brainiac361 ¶

19 years ago


The %[^[]]-trick may seem to work, but it doesn't!

What happens is that sscanf will simply match any characters but an opening square bracket (which is rather rare and that's why it might just seem to work).
But even worse it will expect a ]-character next and continue to match anything.

Now what you can do is make sscanf look for any character but a character that is really never used... a good choice is the linebreak "%[^\\n]", especially in combination with fscanf.

What you can also do is copy and paste any unused ascii character like #001 or something.

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leg ¶

16 years ago


@mikewillitsgmail.com:

<?php

$out = sscanf('file_name.gif', 'file_%[^.].%s', $fpart1, $fpart2);

echo '<pre>';
print_r($fpart1);
echo '<hr />';
print_r($fpart2);
echo '</pre>';

?>

output:

name
-
gif

The "^." part avoid the first searched string to be too greedy. But doesn't protect you against an "file_test.name.gif" input, with bad results!

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Victor ¶

12 years ago


One thing to note: unlike C/C++, a variable %n is assigned to will be counted in the return value.

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Vincent Jansen ¶

19 years ago


If you just wants filter out information between two parts of a string, i used the following, it works better for me then the sscanf function. 

<?php
function scanstr($zoekstr,$part1,$part2) {
$firstpos=strpos ($zoekstr, $part1)+strlen($part1);
$lastpos=strpos ($zoekstr, $part2);
$scanresult=substr ($zoekstr, $firstpos, $lastpos-$firstpos);
    return($scanresult);
}
echo scanstr ("var1=hello&var2=test&var3=more","var2=","&var3");
?>

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anonymouse ¶

18 years ago


I've seen several examples of people using brackets to define what look like regexp character classes. In my limited testing I don't think they are genuine character classes but they seem to be similar.

My task was to use sscanf() to parse an array of strings with the format:

number SPACE string_which_may_also_have_spaces

The normal %s conversion command treats spaces as some kind of delimiter. So, you can get the strings if you know beforehand how many "words" there will be. But, my input was variable.

Here's what I came up with: (note use of the dollar-sign 'end of string' hidden delimiter)

sscanf($string_to_parse,'%d %[^$]s',$num,$text);

This conversion command says "look for an integer, then a space, then any string up to the end of the string"

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codeslinger at compsalot dot com ¶

19 years ago


Security Note:

Although it is a very powerful technique, keep in mind that it is easily deceived.

Many successful exploits have been based on scanf attacks.  It should not be used on untrusted input without a lot of additional validation.

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skeltoac ¶

18 years ago


To parse a line from an Apache access log in common format:

<?php
$log = array();
$n = sscanf(trim($line), '%s %s %s [%[^]]] "%s %s %[^"]" %d %s "%[^"]" "%[^"]"',
    $log['ip'],
    $log['client'],
    $log['user'],
    $log['time'],
    $log['method'],
    $log['uri'],
    $log['prot'],
    $log['code'],
    $log['bytes'],
    $log['ref'],
    $log['agent']
);
?>

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narainsbrain at yahoo dot com ¶

23 years ago


apparently, sscanf always splits at spaces, even if spaces are not specified in the format. consider this script:



<?php

$str = "This is a\tsentence with\ttabs";

$scanned = sscanf($str, "%s\t%s\t%s");

echo join(" : ", $scanned);

?>



this echoes "This : is : a", not the expected "This is a : sentence with : tabs."

this behaviour is fine if your strings don't contain spaces, but if they do you'd be better off using explode().

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Philo ¶

4 years ago


It should also be noted that when used with sscanf both x and X produce the same output (i.e. they are case-insensitive).

<?php
var_dump(sscanf("0xdead|0XDEAD", "%X|%x")); // works

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joshmckenneyATgmailDOT(0{ ¶

19 years ago


added country code (1) to phone number function:

function formatPhone($phone) {
       if (empty($phone)) return "";
       if (strlen($phone) == 7)
               sscanf($phone, "%3s%4s", $prefix, $exchange);
       else if (strlen($phone) == 10)
               sscanf($phone, "%3s%3s%4s", $area, $prefix, $exchange);
       else if (strlen($phone) > 10)
               if(substr($phone,0,1)=='1') {
                                 sscanf($phone, "%1s%3s%3s%4s", $country, $area, $prefix, $exchange);
                             }
                             else{
                                 sscanf($phone, "%3s%3s%4s%s", $area, $prefix, $exchange, $extension);
                                }
       else
               return "unknown phone format: $phone";
       $out = "";
       $out .= isset($country) ? $country.' ' : '';
       $out .= isset($area) ? '(' . $area . ') ' : '';
       $out .= $prefix . '-' . $exchange;
       $out .= isset($extension) ? ' x' . $extension : '';
       return $out;
}

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-1

clcollie at mindspring dot com ¶

24 years ago


Actually sscanf()_always_ returns an array if you specify less return variables than format specifiers. i may change this to return a scalar if only a single format specifier exists.

  Note that sscanf() is (almost) the complete functional equivalent of its "C" counterpart, so you can do the following to get the expected effect :



   sscanf("SN/2350001","SN/%d",&$serial)



The array return was a nicety for PHP.

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-3

marcus at synchromedia dot co dot uk ¶

21 years ago


In PHP >= 4.3.0, if you use additional reference parameters, you will get this warning:

PHP Warning:  Call-time pass-by-reference has been deprecated - argument passed by value

This clearly has the potential to cause unexpected consequences (vars left empty), and will break existing code. So don't do it! These docs need updating to say this too.

The syntax:

    list($a, $b) = sscanf("hello world", "%s %s");

will work as expected, and doesn't seem to cause any problems with Apache that I've noticed.

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-4

sbarnum.pointsystems@com ¶

21 years ago


More fun with phones!  This assumes that the phone number is 10 digits, with only numeric data, but it would be easy to check the length of the string first.

function formatPhone($phone) {
        if (empty($phone)) return "";
        sscanf($phone, "%3d%3d%4d", $area, $prefix, $exchange);
        $out = @$area ? "($area) " : "";
        $out .= $prefix . '-' . $exchange;
        return $out;
}

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-9

nmmm at nmmm dot nu ¶

12 years ago


This is more like C/C++ example, but works on PHP too.



<?php

$qs = "index.php?id=34&name=john";



print_r(   sscanf($qs, "%[^?]?%[^?]")   );



$qs = "id=34&name=john";



print_r(   sscanf($qs, "id=%[^&]&name=%[^&]")   );

?>

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-10

Igor Feghali ¶

16 years ago


parses an input string with fixed field sizes that contains data with spaces:

<?php
$result = sscanf("  Vendor: My Vendo Model: Super Model Foo  Rev: 1234",  
                 '  Vendor: %8[ -~] Model: %16[ -~] Rev: %4c',
                 $vendor, $model, $rev);
?>

$vendor => My Vendo
$model => Super Model Foo 
$rev => 1234

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